// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/base/view_prop.h"
#include "base/macros.h"

#include <set>

namespace ui {

// Maints the actual view, key and data.
class ViewProp::Data : public base::RefCounted<ViewProp::Data> {
public:
    // Returns the Data* for the view/key pair. If |create| is false and |Get|
    // has not been invoked for the view/key pair, NULL is returned.
    static void Get(gfx::AcceleratedWidget view,
        const char* key,
        bool create,
        scoped_refptr<Data>* data)
    {
        if (!data_set_)
            data_set_ = new DataSet;
        scoped_refptr<Data> new_data(new Data(view, key));
        DataSet::const_iterator i = data_set_->find(new_data.get());
        if (i != data_set_->end()) {
            *data = *i;
            return;
        }
        if (!create)
            return;
        data_set_->insert(new_data.get());
        *data = new_data.get();
    }

    // The data.
    void set_data(void* data) { data_ = data; }
    void* data() const { return data_; }

    const char* key() const { return key_; }

private:
    friend class base::RefCounted<Data>;

    // Used to order the Data in the map.
    class DataComparator {
    public:
        bool operator()(const Data* d1, const Data* d2) const
        {
            return (d1->view_ == d2->view_) ? (d1->key_ < d2->key_) : (d1->view_ < d2->view_);
        }
    };

    typedef std::set<Data*, DataComparator> DataSet;

    Data(gfx::AcceleratedWidget view, const char* key)
        : view_(view)
        , key_(key)
        , data_(NULL)
    {
    }

    ~Data()
    {
        DataSet::iterator i = data_set_->find(this);
        // Also check for equality using == as |Get| creates dummy values in order
        // to look up a value.
        if (i != data_set_->end() && *i == this)
            data_set_->erase(i);
    }

    // The existing set of Data is stored here. ~Data removes from the set.
    static DataSet* data_set_;

    const gfx::AcceleratedWidget view_;
    const char* key_;
    void* data_;

    DISALLOW_COPY_AND_ASSIGN(Data);
};

// static
ViewProp::Data::DataSet* ViewProp::Data::data_set_ = NULL;

ViewProp::ViewProp(gfx::AcceleratedWidget view, const char* key, void* data)
{
    Data::Get(view, key, true, &data_);
    data_->set_data(data);
}

ViewProp::~ViewProp()
{
    // This is done to provide similar semantics to SetProp. In particular it's
    // assumed that ~ViewProp should behave as though RemoveProp was invoked.
    data_->set_data(NULL);
}

// static
void* ViewProp::GetValue(gfx::AcceleratedWidget view, const char* key)
{
    scoped_refptr<Data> data;
    Data::Get(view, key, false, &data);
    return data.get() ? data->data() : NULL;
}

// static
const char* ViewProp::Key() const
{
    return data_->key();
}

} // namespace ui
